Method and apparatus for testing hermetically-sealed containers

ABSTRACT

A method for automatically detecting unsatisfactorily sealed containers including sequentially receiving, externally pressure modifying and subsequently testing hermetically sealed containers traveling along a conveyed path. The method includes the detection of any impulse that may be emitted as a result of cover diaphragm movement in those container(s) having insufficient vacuum. When such an audible emission occurs, the containers are rejected. The disclosure is also directed to apparatus for accomplishing this method.

United States Patent Nelson 1*Mar. 21, 1972 54 METHOD AND APPARATUS FOR[56] References Cited TESTING HERMETICALLY-SEALED UNITED STATES PATENTSCONTAINERS 1,825,744 10/1931 Landrum ..73/49.3 [721 Invent: Mlch-2,383,936 9/1945 Hohl .....73/49.3 [73] Assignee: Gerber ProductsCompany, Fremont, 2,985,008 5/1961 Renardm "73/452 Mich. 3,513,6895/1970- Nelson ..73/37 Notice: The portion of the term of this patentsubp i E i -L i R, P in qu n I y 1937, has been AssistantExaminer-William A. Henry, I] clalm Attorney-Townsend and Townsend 7[22] Filed Feb 5,19 0 ABSTRACT [21] Appl' 8,906 A method forautomatically detecting unsatisfactorily sealed Reiated Appncation mcontainers including sequentially receiving, externally pressuremodifying and subsequently testing hermetically sealed commuatlon'm'panof Sen 694,444 291 containers traveling along a conveyed path. Themethod in- 1967, eludes the detection of any impulse that may be emittedas a result of cover diaphragm movement in those container(s) havinginsufficient vacuum. When such an audible emission [5i] lnLCl. ..G0lm3/02 voccurs the containers are rejected. The disclosure iS also [58]Field of Search ..73/37, 45.4, 49.3, l2, directed to apparatus f0raccomplishing this method 15 Claims, 2 Drawing Figures VACUUM SAFETY ORREJECT I /90 AIR ONLY ATM i F 8 E L J W6 p [m il MICROPHO E CARTON NCASE CARTON IN 9 20 Q 0 ,OnQ O -BOW D 34 9 I I 34 B I6 1 T CLOSE CLOSEOPEN Q 34 IE IE] 28 27 26 so START CONTROL METHOD AND APPARATUS FORTESTING HERMETlCALLY-SEALED CONTAINERS This application is acontinuation-in-part application of the copending patent applicationbearing Ser. No. 694,444, filed Dec. 29, 1967, now US. Pat. No. 3,513,689, entitled Method and Apparatus for Detecting Dud Containers.

This invention relates to the nondestructive detection of filled,hermetically sealed containers, having insufficient internal vacuumresulting from instances of imperfect sealing of the container. Moreparticularly, the present invention includes a remotely actuatedapparatus for automatically and rapidly detecting the presence of dudcontainers in amongst a plurality of conveyed cartons.

In the packaging of perishable products, such as baby food, reduction inthe amount of oxidizing gas within the package is employed to lessen thepossibility of spoilage occuring during the storage interval. In orderto ensure a diminished amount of oxidizing gas within the container,i.e., that the contents of the container are under reduced pressure,such perishables are conventionally packaged at elevated temperatures.Minimizing the concentration of oxidizing gas within the head spacebetween the top of the container contents and the closure member isaccomplished by applying the closure member while the perishablecontents are hot and the oxidizing gas within the container is in agreatly expanded (diluted) condition. Thereafter, when the contents ofthe sealed container cool down, the ultimate internal pressure will beless than atmospheric, i.e., a partial vacuum will be present within thecontainer. Provided that the container is properly sealed, the partialvacuum will remain indefinitely. However, if the seal is defective, airwill leak into the container until no pressure differential remains.

To provide for a subsequent visual observation of the continuedexistence of this partial vacuum, containers have been developed thatinclude a sealing member having a flexible area (diaphragm) adapted tooccupy one position (concave) when subjected to a pressure in excess ofa predetermined differential, but be deflected to a second position(convex) in the absence of said predetermined differential. The designand material stresses of the diaphragm are such that deflection occurswithout permanent deformation of the closure member. Such containers areexemplified by mason jars, conventional baby food jars and various typesof tin cans.

Irrespective of the form of the container, the reason for having thisdiaphragm is to provide a visual means to readily determine the presenceof the desired internal vacuum. Thus, where the relationship between theinternal and external pressure is such that a predetermined pressuredifference is present, it will cause this diaphragm to be drawn in,whereas the absence of this predetermined pressure difference will allowthe diaphragm to spring back or occupy a normally unbiased (convex)position. Thus, the absence of an inward distortion of the centerdiaphragm of a filled container after processing is a visuallyobservable indication of an unsatisfactory hermetic seal within thecontainer. Such containers are commonly referred to as duds."Conversely, the continued presence of the inwardly distorted centerdiaphragm also provides a visually observable indication of asatisfactory aseptic condition within the container. This visual aspectis especially useful to the ultimate consumer who can readily determinethe aseptic condition of the container immediately prior to utilizingthe contents thereof.

The above-referenced copending patent application describes a method ofexamination of such containers by detecting the audible impulse emittedby deflection of the diaphragm should insufficient internal vacuum bepresent. This is accomplished by subjecting the containers to sufficientexternal positive pressure to cause any improperly disposed (convex)diaphragm to be forced to the concave position with attendant detectableemission.

Briefly stated, the method of that application includes placing at leastone container within a pressure chamber. The pressure in the chamber isfirst raised to a predetermined positive test limit and thereafterlowered back to atmospheric pressure. In such raising and lowering ofthe pressure interior of the chamber, the diaphragm of a containerhaving insufficient vacuum is deflected from a convex to a concaveconfiguration and thereafter back to a convex configuration. Thisproduces, within the pressurized chamber, audible clicks that aredetectable by a transducer such as a microphone. As the occurrence ofthis distinctive clicking sound alone indicates the presence ofcontainers having insufficient vacuum, detection of insufficientlysealed or dud containers is possible without time consuming andlaborious visual or physical inspection of the food containers.

Heretofore, testing for dud containers has been done merely on a randomsample basis. While such sampling is a statistical indication of thepresence of insufficiently sealed containers, it is preferred,especially in the food products for consumption 'by the very young, totest each and every container emanating from a given food processingplant. The present invention is directed in part to automation of theabove-referenced container testing process by a modern highspeedconveyor system.

In such automation, several distinct problems have been encountered.First, it has been found that the listening transducer is sensitive toextraneous noises from the pressure chamber doors and case movement.Secondly, it has been found that a mere perceptible indication of thepresence of a food container having insufficient vacuum isunsatisfactory as operators are susceptible to human error. Thirdly, ithas been found essential to provide the test apparatus with a sequencethat receives, tests and ejects cartons of encased containers rapidly toenable testing a large portion or possibly the entire output of a foodprocessing plant.

Thetinvention is also directed to apparatus for ensuring that anyexisting partial vacuum within the container be sufficient to providethe necessary storage environment. Thus, in certain instances,containers can include sufficient reduced internal pressure (partialvacuum) at the time of testing to retain the diaphragm in a biased(concave) position. However, such containers may be leaking" slowly andultimately exhibit insufficient vacuum to provide the protectionnecessary for the container contents. Where it is desired to detect suchcontainers, application of a partial vacuum to the outside of thecontainer corresponding to the partial vacuum desired within thecontainer, will cause the flexible diaphragm to spring back to or occupythe normally unbiased (convex) position, thereby creating a detectableimpulse. When the vacuum is released, the diaphragm returns to theconcave position with an accompaning second impulse.

As hereinafter described in more detail, the apparatus of this inventioncan be utilized by applying either a pressure or partial vacuum (or eachin sequence) to the exterior of multiple containers, with the advantagethat containers having an internal vacuum either insufficient tomaintain the diaphragm in the biased position or insufficient to retainthe diaphragm in an unbiased position when subjected to an externalvacuum, can be detected.

Accordingly, an object of this invention is to provide a method forrapidly testing groups of carton-encased, hermetically sealed containersto determine the presence of insufficient internal vacuum. Typicalapparatus includes a pressure chamber provided with front and rearopenings, such as doors, and a conveyor running therethrough. Theconveyor transports the encased containers into the chamber. Thereafter,the doors are closed, sealing the chamber and the pressure thereinsequentially modified. Only during that period after all door and cartonmovement has ceased is the chamber pressure varied from atmospheric,i.e., increased or decreased, and a listening transducer actuated withinthe chamber interior to detect any distinctive click of the manipulatedcover diaphragms. When no containers having unsatisfactory vacuum arefound, the internal pressure is allowed to return to atmospheric, therear pressure chamber door is opened, and the cartons of containers aretransported out of the chamber. If, however, the presence of a containerwith insufficient (unautomatically testing a plurality of hermeticallysealed containers enclosed in at least one opaque shipping carton.

An advantage of this invention is that the transducer is activated onlywhen all movement interior of the pressure chamber has ceased, therebyeliminating the possibility of any extraneous noise interfering with thesignal intended to activate the rejection mechanism.

An additional advantage ofthe apparatus of this invention is that itprovides a vessel in which the pressure can bequickly adjusted andreturned to atmospheric to provide for the testing of all casesemanating from a given manufacturing facility.

A further advantage of this invention is that the rejection mechanisminterrupts the normal sequence of conveyance for cases having dud"containers detected therein, thereby eliminating the possibility ofpassing detected containers having insufficient vacuum. I

Still another advantage of the present invention is that'the testing canbe accomplished without destroying or in any way damaging the opaque,sealed fiber shipping carton conventionally used for storing andshipping of groups of containers.

Other objects, features and advantages of the present invention will bemore apparent after referring to the following specification andattached drawings in which:

FIG. 1 is a schematic illustration of the pressure chamber (shown insection) and attached apparatus installed within a conveyor line; and,

FIG. 2 is a schematic diagram illustrating a circuit for actuating theoperating sequence of the apparatus of FIG. 1.

With reference to FIG. 1, which illustrates a typical apparatusforaccomplishing the process of this invention, a pneumatic detectionsystem is illustrated including pressure chamber A (shown schematicallyin section) having remotely actuated front door B and rear door C. DoorsB and C are tapered internally and externally so that when closed, theywedge into recesses in the respective ends of chamber A, thus sealingits interior. Doors B and C are provided with internal and externalperipheral gaskets (not shown) to ensure that chamber A will be airtight whether pressure is applied or a vacuum drawn. Conveyors D and D,respectively, are ar- When cartons E have fully entered chamber A, limitvalve 3 is activated stopping-conveyor motor 16 and closing door B byactivating cylinder40. Thereafter, chamber A is subjected to theprescribed internal pressure or partial vacuum by introducing orremoving air through conduit F. Once the pressure (or vacuum) interiorof the chamber reaches the desired predetermined test limit, it isallowed to discharge.

Simultaneously with adjusting of the pressure within chamber A,microphone G is actuated. This microphone and related transducer arearranged to detect sonic impulses emanating as a result of the pressuremanipulation of cover diaphragms of those carton encased food containersthat may have insufficient vacuum therein.

In the event that the presence of a container having insufficient vacuumis detected, whether during the pressure or vacuum cycle, dud containervisual indicator (here shown as red light 26) is illuminated and thenon-atmospheric condition withinthe chamber immediately released. Door Bis then ranged to advance carton encased hermetically sealed containersE into, through and out of chamber A. Cartons E are conventional gaspervious, opaque shipping cartons typically containing 24-5 oz.glassbaby food jars. 7

Pressure interior of chamber A is (I) raised and lowered by airintroduced and exhausted through air piping F from an air source (notshown), or (2) lowered by activation of a vacuum source (not shown).Microphone G, activated only when all case and door movement has ceasedwithin the chamber, is provided to detect any distinctive clicking thatmay be emitted by pressure manipulation of the food container diaphragmsin the event that any of the containers within cartons E haveinsufficient internal vacuum.

In operation, cartons E containing a plurality of glass jars are placedon conveyor D immediately outside of chamber A. Door B is in the openposition and the ready for test" indicator (here shown as green light28) illuminated. Start controls 14, comprising a pair ofindependent'buttons P1 and P2, are

then depressed. This pair of buttons must be simultaneously depressed,thereby inhibiting possible hand injury to the operator. It will beapparent to one skilled in this art that where safety is not a primaryconsideration, only one starter button need be included. I

When start controls 14 are depressed, conveyor motor 16 is actuatedthereby advancing conveyors D and D and causing cartons E to moveforwardly and inwardly interior of chamber A. Simultaneously, test inprogress visual indicator (here shown as blue light 22) is illuminated.

opened and conveyor motor 16 reversed so that cases E are returned tothe operator in the position indicated in FIG. 1.

Assuming that all containers in cartons E have sufficient vacuum, thepressure (or vacuum) within chamber A is released, i.e., allowed toreturn to a level near atmospheric, and the connection betweenmicrophone G and its associated transducer is interrupted. Thereafter,rear door C is opened, conveyor D actuated in the forward direction toconvey cases outwardly of the pressure chamber and onto a conveyor 20from where the cartons E are advanced or conveyed to a position clear ofthe chamber. When cartons E are clear of chamber A, as detected by limitvalve 6, rear door C is closed, and front door B opened placing chamberA in readiness for its next sequential test of cartons.

In accordance with the standard practices pertaining to pressurevessels, the chamber A of this invention is equipped with a safety valve90, which valve is designed to prevent air pressure accumulatinginterior of the chamber'A exceeding a predetermined limit.

Although the apparatus of this invention is equally functional withvacuum or pressure conditions, for convenience the remainder of thisdescription will relate to detection during the application of externalpressure.

Referring now to FIG. 2, which depects a 'methodfor accomplishing thisinvention, the operation of a pneumatic circuit sufficient for thepractice of this invention is schematically illustrated. In suchillustration it will be convenient to first set forth the sequence whereno dud container is detected and thereafter the sequence where thepresence of a dudv container is detected. 7

In describing the operation of the schematic circuit of FIG. 2,reference will be made to valves 38, 46, and 60. These valves areillustrated as two-position pneumatic valves having generally one inletand two outlets. Typically, valve blocks between the inlets and outletsare moved by a pressure impulse from various other portions of thecircuit. When these pressure impulses are received,. the valve blockshifts as described in the following specif cation communicating theinlet to one or the other of the outlets.

Referring to FIG. 2, an air supply (not shown) isconnected by line 23 tobuttons P1 and P2 of dual hand start control 14. These buttons,connected in series for operation by both hands of the operator supplyactuating air to the circuit and impart an actuating pulse. through line24 to the forward" section of motor control 25. Simultaneously, animpulse is communicated to blue test in progress indicator 27 causingillumination of indicator 27 and concurrent extinguishment of indicator28.through connected circuitry (not shown). Additionally, start control14 functions to pass actuating air to the remainder of the circuitthrough air supply lines 30.

Motor 32, actuated by the forward" section of start control 25 causesconveyors D and D to move cartons E forwardly through-belt and shaftdrives 347(shown in FIG. 1).

When limit valve 3 senses the full entry of the conveyed cases- .E intochamber A, it actuates-two functions-through its connected line 36.First, a pressure signal is communicated tothe stop" section of conveyorcontrol 25, stopping conveyor motor 32. Secondly, a pressure impulse iscommunicated to control block 26 to front door control valve 38. Thiscontrol block shifts to a position where it registers inlet 29 betweenair supply 30 and line 39 to cylinder 40. Cylinder 40 supplied withactuating air through line 39, closes front door B.

Limit valve 2 detects closing of front door B. Valve 2 actuates twofunctions. First, through line 42, a pressure signal is communicated tobypass circuit 43. Bypass 43 functions to hold open an air passageacross start control 14 permitting the operator to remove his hands fromdual hand control 14. Secondly, through line 44, the flow of air intochamber A is initiated by shifting the control block of control valve 46to a position where it permits the flow of air through line 47 frompressure reducing valve 48 to chamber A.

In operation, pressure reducing valve 48 is set to the maximum testpressure desired within chamber A. Air passes through pressure reducingvalve 48 from air supply line 30 and interior of chamber A. Typically,flow of this air is throttled to provide within chamber A a gradualincrease in pressure.

Once the chamber pressure begins to rise to a level such as 0.5 to lp.s.i.g., microphone G is energized. This occurs through closing ofnormally open, pressure closed circuit 50 connected between microphone Gand its transducer 52. Circuit 50 maintains microphone G energizedduring that period of time that chamber A contains a positive levelpressure above 0.5 to 1.0 p.s.i.g.

When the throttled inflow of air interior of chamber A has caused thepressure to reach the maximum desired state (typically in the range of25 to 30 p.s.i.g.), the air pressure within chamber A is relieved.Maximum pressure sensor 55, through piping connected to chamber A,detects the presence of maximum test pressure within the chamber.Thereafter, this sensor communicates an impulse to the control block ofchamber air control valve 46 to shift the block to the exhaust position.In this position of valve 46, piping F is registered with the exhaustport of valve 46. Air from chamber A discharges through a connectedexhaust muffler provided for noise attenuation. Similar to the casewhere air is inflowed to chamber A, air out flowing from chamber A isthrottled to provide for substantially gradual pressure reductioninterior of the chamber.

Assuming no dud" container is detected, when the pressure interior ofchamber A approaches atmospheric, normally open pressured closed circuit50 returns to the open position, interrupting the connection betweenmicrophone G and transducer 52. Thereafter, minimum pressure sensor 56through line 57 detects when the chamber has reached substantiallyatmospheric pressure. Upon this detection, sensor 56 communicates apressure signal to rear door control valve 60 through line 59. Controlvalve 60 has its control block shifted so as to provide an air passagefrom air supply line 30 through the valve to rear door opening piping61. Air passing through piping 61 causes rear door control cylinder 62to shift rear door C to the open position.

Once rear door C is in the open position, it triggers limit valve 5.Limit valve 5 provides a signal through line 64 to the forward sectionof conveyor control 25. Control 25 causes conveyor motor 32 to onceagain move conveyors D and D forwardly conveying carton E out of chamberA and onto conveyor (see FIG. 1).

When the cases have passed onto conveyor 20, they are advanced down thegradual slope of the conveyor until they make contact with limit valve6. Valve 6 tripped by the mass of passing cartons E, simultaneouslytriggers two functions. First, through line 66, valve 6 causes conveyorcontrol to stop motor 32 and connected conveyors D and D. Secondly,through line 68, valve 6 causes the control block of rear door controlvalve 60 to shift. This shift of the block causes air to be communicatedfrom air supply line to the bottom of cylinder 62 causing rear door C toclose.

When rear door C closes, limit valve 4 detects such closure. This limitvalve through a line 70 communicates a pressure signal to frontdoorcontrol valve 38. Valve 38 has its control block moved to the dooropen position and air flowing through front door opening piping 72causes front door control cylinder 40 and connected front door B to moveto the open position.

On movement of the front door to the open position, limit valve 7 isactuated. Valve 7, through connected line 73, effects two functions.First, bypass 43 has a pressure signal communicated thereto which closesthe bypass. This signal closes down the actuating air supply acrossstart control 14. Secondly, line 73 furnishes an impulse to the "readyfor test" visual indicator 28 here shown as a green light. Thisindicator upon receiving an impulse turns off indicator 27 (throughcircuitry not shown) and emanates a visual signal indicating that themechanism is ready to receive its next sequential cartons E for test.

The foregoing description has been made with the assumption thatmicrophone G receives no impulse indicating the presence of a foodcontainer having unsatisfactory vacuum. Assuming that such a conditionis detected, the operation of the schematic circuit illustrated in FIG.2 will now be described.

When the pressure increase within chamber A causes a cover on ahermetically sealed container having insufficient vacuum to move fromthe convex to concave configuration, a distinctive clicking sound willemanate. This sound will be detected by microphone G. Microphone G,connected across the normally closed pressure opened switch 50 totransducer 52, will cause a pressure signal to be emitted from thetransducer at lines 75 and 77 respectively. Line 76 will emanate a pulseto dud container visual indicator 26 (here shown as a red light) whichwill be illuminated, turning off the test in progress visual indicator27 through circuitry (not shown). Simultaneously, line 77 will transmita signal to test pressure control valve 46 causing this valve to shiftimmediately to the exhaust position. Additionally, a pressure impulsewill be received at minimum pressure sensor 56 causing its outlet to bediverted from line 59 to line 80.

Chamber A will exhaust its pressurized air through air piping F. Whenthe pressure within the chamber has reached a minimum level, minimumpressure sensor 56 through line 57 will detect this pressure level andcommunicate a pressure signal through line 80 instead of line 59. Line80 will in turn communicate a pressure impulse to front door controlvalve 38.

Valve 38 through the shift of its control block will communicate airfrom inlet piping 30 to door opening piping 82 causing cylinder 40 toopen front door B. Virtually simultaneously, line 80 at a secondconnection will actuate the reverse section of conveyor control 25causing conveyor motor 32 to operate in reverse. Cartons E interior ofchamber A will move on conveyors D and D' from the interior of thechamber A back along the original conveyed path through open front doorB returning to the operator.

When cartons E have been conveyed clear of chamber A, they will actuatelimit valve 8. Valve 8 through its line 86 will actuate the stop sectionof conveyor control 25. This will stop motor 32 arresting furtherconveyor motion. Substantially at the same time, front door B in movingto the open position will trigger limit valve 7. Valve 7 will closebypass circuit 43 and illuminate ready for test indicator 28 in themanner previously described. The machine is thus returned to adisposition where it is ready for its next sequential test.

Referring again to testing conducted while drawing a vacuum in chamberA, vacuum grading can be accomplished by subjecting the containers to aspecific level of vacuum. Thus, if it is desired to grade out allcontainers having less than 5 inches Hg vacuum, a typical procedurewould be to determine the amount of vacuum needed to hold the diaphragmin a concave (biased) position. Thereafter a vacuum slightly in excessof the difference between the diaphragm holding vacuum and the desiredgrade of vacuum within the containers would be externally applied.

The invention herein has been described schematically by use of apneumatic circuit. It should be understood that other sequentialcontrols, well known in the art (such as electrical, mechanical, andhydraulic) can all be used. Furthermore,

where high quality control conditions are present, a chambercan beutilized that is of sufficient dimensions to receive a plurality ofcartons such as would be stored, for example, on a shipping pallet.Thus, a rapid means is provided for simultaneously testing a largenumber of containers to ensure high quality product control. Likewise,these and other modifications of my invention may be practiced, it beingunderstood that the form of my invention as described above is to betaken as a preferred example of the same. Such description has been byway of illustration and example for purposes of clarity andunderstanding. Changes and modifications may be made without departingfrom the spirit of my invention.

lclaim:

1. A method for testing hermetically sealed containers, each containerhaving a pressure flexible diaphragm adapted to emit a detectableimpulse when flexed by relative pressure changes between the inside andoutside of said container, the steps of: providing a vessel having atleast one scalable opening; conveying said entire container into saidvessel through said opening; sealing said opening to said vessel;modifying the pressure within said vessel; detecting anyemitted impulseswithin said vessel only when said pressure is varied interiorly thereof;providing a second opening from said vessel for egress of saidcontainer, and, conveying said container out of said second opening insaid vessel.

2. A method in accordance with claim 1 wherein the internal vesselpressure is modified by increasing it above atmospheric.

3. A method in accordance with claim 2.wherein the increased pressure isreleased before said container is conveyed out of said opening.

4. A method in accordancewith claim 3 wherein a partial vacuum iscreated in said vessel prior to increasing said pressure.

5. A method in accordance withclaim 1 wherein said container tested isone of a plurality of containers enclosed in opaque, gas-perviouscartons.

6. Apparatus for testing a hermetically sealed container having apressure actuatable diaphragm portion in at least one wall thereof, toindicate insufficient vacuum upon flexure of said diaphragm portion byexternal pressure changes upon said container, said apparatuscomprising: a pressure vessel; conveyor means extending into saidpressure vessel for conveying said container along a predetermined path;means for actuating said conveyor means for transporting said containerinto said pressure vessel; means for sealing said vessel when saidcontainer is therewithin; means for varying the pressure within saidsealed vessel when said container is therewithin; meanstodetect soundemanating from said diaphragm portion within said vessel responsive topressure changes within said vessel; and means responsive to said sounddetecting -means for diverting said container from said predeterminedcontainer into and out of said vessel.

10. The apparatus of claim 6 and wherein said diverting means includesmeans for reversing said conveyor means.

11. In combination: at least. one container having a diaphragm includedin at least one wall thereof for sound emanating flexure' by pressurevessel; conveyor means extending into said t pressure vessel; means foractuating said conveyor means or transporting said container Into saidpressure vessel; means for sealing said vessel when said container istherewithin; means for varying the pressure within said sealed vessel;and means to detect sound emanating from said diaphragm within saidchamber only when pressure is varied within said sealed vessel.

12. The invention of claim 1 1 wherein said pressure varying meanscomprises vacuum drawing means and pressure increasing means actuatablein sequence.

13. The invention of claim 11 and wherein a plurality of said containersare transported simultaneously into said vessel for test.

14. The invention of claim 11 and including means for diverting saidcontainers from said conveyed path, said diverting means operativelyresponsive to sound, detected by said detecting means. i

15. A method for testing hermetically sealed containers on a moving lineof containers, each container having a pressure flexible diaphragmadapted to emit a detectable impulse should relative pressure changesbetween the insideand outside of said container cause flexing of saiddiaphragm, the steps of: moving a group of said containers to be testedto within a pressure scalable chamber; sealing said chamber;

varying the pressure withinsaid chamber containing said containers;detecting any emitted impulses" within said sealed chamber while saidpressure is varied therein; restoring the pressure within said chamber;removing said containers from said chamber; and separating thosecontainers that emit said detected impulses from other'of saidcontainers. v

1. A method for testing hermetically sealed containers, each containerhaving a pressure flexible diaphragm aDapted to emit a detectableimpulse when flexed by relative pressure changes between the inside andoutside of said container, the steps of: providing a vessel having atleast one sealable opening; conveying said entire container into saidvessel through said opening; sealing said opening to said vessel;modifying the pressure within said vessel; detecting any emittedimpulses within said vessel only when said pressure is varied interiorlythereof; providing a second opening from said vessel for egress of saidcontainer, and, conveying said container out of said second opening insaid vessel.
 2. A method in accordance with claim 1 wherein the internalvessel pressure is modified by increasing it above atmospheric.
 3. Amethod in accordance with claim 2 wherein the increased pressure isreleased before said container is conveyed out of said opening.
 4. Amethod in accordance with claim 3 wherein a partial vacuum is created insaid vessel prior to increasing said pressure.
 5. A method in accordancewith claim 1 wherein said container tested is one of a plurality ofcontainers enclosed in opaque, gas-pervious cartons.
 6. Apparatus fortesting a hermetically sealed container having a pressure actuatablediaphragm portion in at least one wall thereof, to indicate insufficientvacuum upon flexure of said diaphragm portion by external pressurechanges upon said container, said apparatus comprising: a pressurevessel; conveyor means extending into said pressure vessel for conveyingsaid container along a predetermined path; means for actuating saidconveyor means for transporting said container into said pressurevessel; means for sealing said vessel when said container istherewithin; means for varying the pressure within said sealed vesselwhen said container is therewithin; means to detect sound emanating fromsaid diaphragm portion within said vessel responsive to pressure changeswithin said vessel; and means responsive to said sound detecting meansfor diverting said container from said predetermined path.
 7. Theapparatus of claim 6 wherein said pressure varying means comprisesvacuum drawing means and pressure increasing means actuatable insequence.
 8. The invention of claim 6 and wherein said sound detectingmeans is adapted to detect sound only when said pressure is variedwithin said sealed vessel.
 9. The apparatus of claim 6 and wherein saidsealing means includes first and second doors in the walls of saidpressure vessel; and said conveyor means is adapted to transport saidcontainer into and out of said vessel.
 10. The apparatus of claim 6 andwherein said diverting means includes means for reversing said conveyormeans.
 11. In combination: at least one container having a diaphragmincluded in at least one wall thereof for sound emanating flexure bypressure vessel; conveyor means extending into said pressure vessel;means for actuating said conveyor means for transporting said containerinto said pressure vessel; means for sealing said vessel when saidcontainer is therewithin; means for varying the pressure within saidsealed vessel; and means to detect sound emanating from said diaphragmwithin said chamber only when pressure is varied within said sealedvessel.
 12. The invention of claim 11 wherein said pressure varyingmeans comprises vacuum drawing means and pressure increasing meansactuatable in sequence.
 13. The invention of claim 11 and wherein aplurality of said containers are transported simultaneously into saidvessel for test.
 14. The invention of claim 11 and including means fordiverting said containers from said conveyed path, said diverting meansoperatively responsive to sound detected by said detecting means.
 15. Amethod for testing hermetically sealed containers on a moving line ofcontainers, each container having a pressure flexible diaphragm adaptedto emit a detectable impulse should relative pressure changes betweenthe inside and outside of said container cause flexing of saiddiaphragm, the steps of: moving a group of said containers to be testedto within a pressure sealable chamber; sealing said chamber; varying thepressure within said chamber containing said containers; detecting anyemitted impulses within said sealed chamber while said pressure isvaried therein; restoring the pressure within said chamber; removingsaid containers from said chamber; and separating those containers thatemit said detected impulses from other of said containers.